U.S. Pat. No. 4,039,886, Scherzer, assigned to a related company of the assignee of the present application, describes a contact pin insulation of terminal connectors for infrared radiators. The base is formed as a sleeve surrounding the contact pin. The inner surface of the insulation sleeve, which is made of plastic material, is formed with recesses or projections, respectively, for interengagement of the terminal contact with the insulation sleeve. When the temperature of operation becomes very high, plastics used as insulation sleeves have problems with respect to temperature resistance, and long-term stability, so that such sleeves are not suitable for radiators operating at high temperatures.
It has been proposed, see German 43 40 995 A1, Dieudonne et al. assigned to a related company of the present application, to protect pinch or press ends of radiators by plastic sleeves which can be slid on the pinch seals. Such plastic sleeves are not suitable for radiators operating at high temperatures, since long-term stability is a problem. This is particularly so if the radiators are mercury arc high-pressure discharge lamps.
German 39 34 348 C2, Bernd Ullrich et al, describes an electrical discharge lamp with a tubular bulb of quartz glass. Axially oppositely located electrodes are pinch-sealed through the lamp bulb. A base is fitted on the pinch-sealed ends of the bulb. The base is made of electrically insulating material, shaped as a hollow cylinder with two oppositely located slit-shaped recesses or cuts to receive the flat ends of the pinch seal. The base has a through-opening or slit in which contact springs are located. The outer edges of the contact springs are secured in groove-shaped inner edges of a rectangular enlargement and retained by spring action. Manufacture of such a lamp and the bases therefor is comparatively complex and expensive and, further, requires shaping of the external contact terminals to cooperate with external contact springs.